Abstract:Schlegel's rockfish(Sebastes schlegeli), distributed in the western North Pacific, is an important offshore cage-culture fish species in the Yellow Sea and Bo-hai Sea of China. Schlegel's rockfish juvenile(TL=55.2mm, 99.0mm, short in SJ and LJ, respectively) were exposed to seawater containing different concentrations of 2-Phenoxyethanol from 200mg/L to 800mg/L, clove oil from 10mg/L to 80mg/L. The respiratory rates and anaesthetic effect of 2-Phenoxyethanol and clove oil were studied. Normally, the respiratory rate of SJ(22.8/10s) was higher than LJ(19.7/10s). The respiratory rate descended remarkably(P<0.001) as the anaesthetic concentration ascended: it would be descended to 0 in short time(shock stage) in high concentration(2-Phenoxyethanol: 500, 600, 800μL/L; clove oil: 60, 80μL/L), descended in different levles in middle concentration (2-Phenoxyethanol: 400μL/L; clove oil: 30、40μL/L), and it has affected mildly in low concentration (2-Phenoxyethanol: 200, 300μL/L; clove oil: 10, 20μL/L). The effects on respiratory rate of SJ were more remarkable than of LJ in the same concentrations (P<0.01). The anaesthetic time, shock time and recovery time of LJ were longer than SJ in 2-Phenoxyethanol. The anti-anaesthetic ability of LJ was stronger than SJ. In recovery ability, the LJ recoveried later than SJ in clove oil seawater, but there was not the similar phenomenon been seen in 2-Phenoxyethanol. By thought of anaesthetic time, shock time, recovery time and mortality, the optimum concentrations of 2-Phenoxyethanol and clove oil were 300μL/L, 20μL/L for use.
